Preparation of functionalized anionic polymerization initiators

ABSTRACT

A process for preparing a functionalized polymerization initiator, the process comprising combining a functionalized styryl compound and an organolithium compound.

This application is the national stage of International Application No.PCT/US03/21871, filed on Jul. 11, 2002, which claims the benefit of U.S.Provisional Application No. 60/395,085, filed on Jul. 11, 2002.

FIELD OF THE INVENTION

This invention relates to novel processes for preparing functionalizedlithium compounds that are useful as initiators for anionicpolymerizations.

BACKGROUND OF THE INVENTION

Conjugated diene monomers are often anionically polymerized by usingalkyllithium compounds as initiators. Selection of certain alkyllithiumcompounds can provide a polymer product having a functionality at thehead of the polymer chain. The ability to head-functionalizeanionically-polymerized polymers has provided many advantages to tiretechnology. For example, lithiated cyclic amines, such as lithiohexamethyleneimine, has been employed to initiate the polymerization ofconjugated dienes, as well as the copolymerization of conjugated dienesand vinyl aromatic monomers, to produce polymers having a cyclic-aminehead functionality. These polymers have proven to providetechnologically useful tire treads that are characterized by improvedtraction, low rolling resistance, and improved wear.

The synthesis of these polymers is advantageously conducted inenvironmentally friendly solvents such as technical hexanes. The hightemperatures at which some polymerizations occur, however, has led tothe problem of reduced head functionality. To alleviate this problem, itwas discovered that the use of cyclic aminoalkyllithium compounds, suchas hexamethyleneimine propyllithium, could withstand high polymerizationtemperatures and thereby lead to polymers having greater functionality.

The preparation of these cyclic aminoalkyllithium compounds, however,has proven to be difficult and inefficient. In one technique, theinitiators are prepared by reacting a cyclic aminoalkyllithium halidewith elemental lithium or an organolithium compound. Where the halide isreacted with elemental lithium, the product must be separated frombyproducts such as lithium metal and lithium chloride mud. Separation ofthese products can prove difficult, in part due to the limitedsolubility of the aminoalkyllithiums. Additionally, the product made bythis route is often contaminated with undesirable side products such asthe products of Wurtz coupling. Moreover, the precursor aminoalkylhalidecompounds are capable of self-quaternization, thus consuming thereactive halide. As a result, it is necessary to store these compoundsat low temperatures or as their hydrohalide salts and liberate theaminoalkylhalide by treatment with base a short time before lithiationis carried out. When the halide is reacted with an organolithiumcompound, the reaction inefficiently requires two or more equivalents oflithium from the organolithium to prevent undesirable side reactionsthat occur between the lithiated amine and the resultant chlorinatedorganic byproducts.

Because cyclic aminoalkyllithium compounds remain useful as initiatorsfor preparing functionalized polymers, there is a need to overcome theproblems associated with the synthesis of these initiators.

SUMMARY OF THE INVENTION

In general the present invention provides a process for preparing acyclic-aminoalkyllithium anionic polymerization initiator, the processcomprising combining a functionalized styryl compound and anorganolithium compound.

The present invention further includes an anionic polymerizationinitiator defined according to the formula I

where each R¹ is independently hydrogen or a hydrocarbyl group, R² ishydrogen or a hydrocarbyl group, R³ is hydrogen or a hydrocarbyl group,each R⁴ is independently hydrogen or a monovalent hydrocarbyl, R⁵ ishydrogen or a hydrocarbyl group, where at least one of R³ or R⁵ ishydrocarbyl, R⁶ is a covalent bond or a hydrocarbylene group, and A is afunctional group.

The present invention still further provides a polymer prepared by aprocess comprising the steps of polymerizing monomer with an initiatorthat is prepared by combining a functionalized styryl compound and anorganolithium compound.

Novel aminoalkyllithium initiators can now be prepared by reacting anorganolithium compound with functionalized styryl derivatives thatcontain cyclic amine functionalities. Advantageously, this discovery notonly solves problems associated with the prior art preparation of cyclicaminoalkyllithiums compounds, but this discovery has also provided amethod whereby a host of functionalized initiators can be prepared bylithiating numerous functionalized styryl derivatives. This lithiationproceeds by way of an addition reaction, which thereby avoidsby-products that result from substitution reactions of the halo alkylprecursors with lithium or lithium-containing compounds and avoids theneed to liberate or treat the quaternized base. Further, because theaddition reaction to the functionalized styryl derivatives occurs at alocation between the amine and phenyl substituents of the styrylderivative, the reaction provides a highly stabilized carbon-lithiumsite.

Also, where the functionalized styryl derivative is prepared by asubstitution reaction in lieu of an addition reaction, the process hasbeen found to be more efficacious because less starting material is lostto the formation of undesirable side-products. The resultantaminoalkyllithium initiators can advantageously be used to preparepolymers that include a functional group at the head of the polymer.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The novel functionalized lithium-containing anionic polymerizationinitiators of this invention are uniquely prepared by combiningfunctionalized styryl reagent with an organolithium reagent.

This initiator can be represented by the formula I

where each R¹, R², R³, R⁴, and R⁵ is independently hydrogen or ahydrocarbyl group, where at least one of R³ or R⁵ are hydrocarbyl, R⁶ isa covalent bond or a hydrocarbylene group, and A is a functional group.

The hydrocarbyl groups include, but are not limited to, alkyl,cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl, substitutedcycloalkenyl, aryl, allyl, substituted aryl, aralkyl, alkaryl, andallynyl groups, with each group preferably containing from 1 carbonatom, or the appropriate minimum number of carbon atoms to form thegroup, up to 20 carbon atoms. These hydrocarbyl groups may containheteroatoms such as, but not limited to, nitrogen, oxygen, silicon,sulfur, and phosphorus atoms.

The hydrocarbylene groups include, but are not limited to, alkylene,cycloalkylene, substituted alkylene, substituted cycloalkylene,alkenylene, cycloalkenylene, substituted alkenylene, substitutedcycloalkenylene, arylene, and substituted arylene groups, with eachgroup preferably containing from 1 carbon atom, or the appropriateminimum number of carbon atoms to for the group, up to 20 carbon atoms.These hydrocarbylene groups may contain heteroatoms such as, but notlimited to, nitrogen, oxygen, silicon, sulfur, and phosphorus atoms.

Advantageously, numerous functional groups can be selected based on theultimate application of the polymer that will be synthesized with theinitiator. Exemplary functional groups include amine groups, phosphinegroups, ether groups, thio ether groups, seleno groups, silyl groups,alkyl tin groups, and short-chain thermoplastic polymer segments.

Useful amine groups include those defined by the Formula II

where each R⁷and R⁸ is independently a hydrocarbyl group or where R⁷ andR⁸ join to form a hydrocarbylene group. Preferably, neither R⁷ nor R⁸ ishydrogen or includes a protonated heteroatom or carbonyl group.

In one embodiment, the hydrocarbyl groups R⁷ and R⁸ join together toform a hydrocarbylene group, which results in a cyclic amine that can berepresented by the Formula III

where each R⁹ is independently hydrogen or a hydrocarbyl group, or whereeach R⁹ join together to form a hydrocarbylene group, which results in abicyclic compound, and where a is an integer from 4 to about 18. Infact, the substituents of formula II can include multi-cyclosubstituents such as tricyclo substituents.

Specific examples of cyclic amine groups include -pyrrolidine,-3-methypyrrolidine, -3,4dimethylpyrrolidine, -3,3-dimethylpyrrolidine,-piperidine, -4-methylpiperidine, -3-methylpiperidine, -morpholine,-4-methylpiperazine, -4-ethyl-piperazine, -4-propylpiperazine,-hexamethyleneimine (or -perhydroazepine), -trimethylperhydroazepine,-azacyclotridecane, -azacyclohexadecane, -azacycloheptadecene,-trimethylazabicycloöctane, -perhydroisoquinoline, and -perhydroindole.

In another embodiment, at least one hydrocarbyl group is a cyclichydrocarbyl group such as a cyclopentane group, a cyclohexane group, acycloheptane group, and the like. In one particular embodiment, thecyclic hydrocarbyl group includes a hetero atom such as, but not limitedto, nitrogen. This cyclic hydrocarbyl group results in a functionalgroup that can be defined, for example, by the formula IV

where R⁷ and R⁹ are as defined above, and R¹⁰ is a hydrocarbyl group.

In another embodiment, preferred hydrocarbyl groups (i.e., R⁷ and R⁸)may include aromatic groups such as, but not limited to, benzene,pyridine, thiophene, furan, N-methylpyrrole and selenophene groups.Other aromatic groups include polynuclear groups such as, but notlimited to pyrene, anthracene and naphthalene.

In another embodiment, the hydrocarbyl group may include a silyl group(e.g., —SiR₃) where R is a hydrocarbyl group as defined above.

Useful phosphine groups include those defined by the formula V

where each R⁷ and R⁸ is independently a hydrocarbyl group as definedabove. Because the phosphine groups are similar in valance to the aminegroups, groups that are analogous to the amine groups defined above areuseful. Examples of phosphine groups include diphenyl phosphine.

Useful ether groups can be defined by the formula VI—O—R⁷  (VI)where R⁷ is a hydrocarbyl group as defined above. One Example of anether group includes those where R⁷ is aromatic, such as

Useful thioether and seleno ether groups can be defined by therespective formulas VII and VIII—S—R⁷  (VII)—Se—R⁷  (VIII)where R⁷ is a hydrocarbyl group as defined above. Because the thio etherand seleco ether groups are similar in valence to the ether groups,groups that are analogous to the ether groups are useful.

Examples of thio ether groups include t-butyl thio ether.

Silyl groups include those defined by the formula IX

where R¹⁰ is a hydrocarbyl group or an alkoxy group.

Examples of silyl groups include trimethyl silyl, triethyl silyl,dimethoxy methyl silyl, and dimethyl methoxy silyl.

While numerous functional groups can be employed, one preferred type offunctional group include those groups that interact or react with rubberfillers. Functional groups that will react or interact with rubberfillers include strong, weak, or selective functional groups. Strongfunctional groups include those substituents that undergo some type ofbonding with the filler, e.g., covalent or ionic bonding. Weakfunctional groups include those groups that interact with filler viathrough-space interaction, e.g., H-bonding or van der Waals interaction,as well as those groups that interact or attract to each other andthereby form a domain within the rubber matrix of the polymer. Selectivefunctional groups include those groups whose affinity toward fillerparticles or rubber can be activated after processing, e.g., duringcure. Examples of selective functional groups include those described inU.S. Pat. No. 6,579,949, which is incorporated herein by reference.

Functional groups that are filler interactive include, but are notlimited to, cyclic amines, alkyl amines, alkyl tins, and trialkoxysilanes.

The initiator of this invention is uniquely synthesized by combining afunctionalized styryl reagent with an organolithium reagent.

The functionalized styryl reagent and the organolithium can be reactedin a 1:1 molar ratio, although an excess of either reagent can beemployed. In a preferred embodiment, an excess of the organolithium isemployed (e.g., 1 mole of organolithium to 0.9 moles of thefunctionalized styryl).

This reaction can take place by contacting the functionalized styryl andthe organolithium under ambient conditions within an inert solvent. Thisreaction can also take place in the presence of monomer. In oneembodiment, the initiator is prepared in situ whereby the reactionbetween the functionalized styryl reagent and the organolithium compoundoccurs in the presence of monomer that is intended to form the mainchain of the resultant polymer.

The reaction preferably takes place in an organic solvent includinganhydrous or non-polar polar solvents and hydrocarbon solvents. Thereaction conditions are preferably the same as those that areconventionally employed when organolithium (e.g., n-butyllithium) isused to initiate and anionic polymerization of conjugated dienes.

The functionalized styryl reagent can be defined by formula X:

where each R¹, R², R³, R⁴, R⁶ and A are as defined as above.

In one embodiment, preferred functionalized styryl reagent is acyclic-amino functionalized styryl reagent, which can be defined by theformula XI:

where each R¹, R², R³, R⁴, and R⁹, and a is defined above. Preferably,each R¹ is a hydrogen atom or an alkyl group including 1 to about 6carbon atoms, R² is a hydrogen atom, an alkyl group containing 1 toabout 6 carbon atoms, or a phenyl group, R³ is a alkyl group containing1 to about 6 carbon atoms, each R⁴ is a hydrogen atom or an alkyl groupcontaining 1 to about 6 carbon atoms, each R⁹ is hydrogen or an alkylgroup including about 1 to about 6 carbon atoms, and a is an integerfrom about 4 to about 12.

Some specific examples of the cyclic-amino functionalized styrylcompounds include N-(cinnamyl): -pyrrolidine, -3-methypyrrolidine,-3,4-dimethylpyrrolidine, -3,3-dimethylpyrrolidine, -piperidine,-4-methylpiperidine, -3-methylpiperidine, -morpholine,-4-methlpiperazine, -4-ethyl-piperazine, -4-propylpiperazine,-hexamethyleneimine (or -perhydroazepine), -trimethylperhydroazepine,-azacyclotridecane, -azacyclohexadecane, -azacycloheptadecene,-trimethylazabicycloöctane, -perhydroisoquinoline, and -perhydroindole.

In one embodiment, the functionalized styryl reagent can be prepared byreacting a reactive styryl reagent with a functionalized nucleophilethat is not reactive toward or less reactive toward the active doublebond (i.e., won't add to the double bond) of the reactive styryl reagentthan toward the carbon bearing the leaving group of the reactive styrylreagent. For example, the preferred cyclic-amino functionalized styrylreagent can be prepared by reacting a reactive styryl reagent (e.g.,cinnamyl chloride) with a cyclic amine (e.g., hexamethylene imine) viasubstitution of an allylic halide.

Alternatively, this can be accomplished via a coupling of an allylicalcohol. For example, a styryl amino compound can be formed by thereaction of a cyclic secondary amine with cinnamyl alcohol in thepresence of tin dichloride and a palladium(0) catalyst. Styryl aminocompounds can also be formed via the displacement of halogen from acinnamyl halide that is treated with a secondary cyclic amine. An excessof the same amine, another amine, or another base can be used as aproton scavenger.

In this embodiment, the reactive styryl reagent can be defined byformula XII:

where each R¹, R², R³, R⁴, and R⁶ is defined as above, and Q is aleaving group. Exemplary leaving groups include halides, ester groups,alkyl or aryl sulfonates, and carboxylates.

Those skilled in the art can envision numerous functionalizednucleophile that can be reacted with the reactive styryl compound toform the functionalized styryl reagent. Examples of functionalizednucleophile include cyclic amines, alkylamines, functionalized alcohols,functionalized thiols, functionalized selenols, and the metal saltsthereof.

The preferred cyclic amine can be defined by the formula XIII:

where each R⁶ and a are defined as above. Useful cyclic amines includepyrrolidine, piperidine, 3-methylpiperidine, 4-alkylpiperazine such as4-propylpiperazine, perhydroazepine, which is also known ashexamethyleneimine, 1-azacyclooctane, perhydroisoquinoline, orperhydroindole.

It is believed that the cyclic amine will displace the leaving group,and the nitrogen atom will bond with or via R⁵ in a nucleophilicsubstitution reaction.

In another embodiment, the functionalized nucleophile is not reactivetoward or less reactive toward the active double bond (i.e., won't addto the double bond) of the reactive styryl reagent than toward thecarbon bearing the leaving group of the reactive styryl reagent.

For example, the reactive styryl reagent can be reacted with a polymerhaving an —OLi group at its tail to form a functionalized styrylreagent. Those skilled in the art appreciate that a polymer having an—OLi at its tail can be prepared by terminating a living polymer with anepoxide. Where the living polymer is initiated with a functionalizedinitiator such as a cyclic amine or a cyclic amino lithium or atrialkyltin lithium, the resulting functionalized stryl reagent willinclude the cyclic amino or trialkyltin group as a functional group.

In this embodiment, the preparation of the functionalized styryl reagentcan be carried out by reacting one mole of the reactive styryl reagentwith one mole of the functionalized nucleophile (e.g., cyclic amine) andone mole of a scavenging or non-nucleophilic base. Those skilled in theart will appreciate that the functionalized nucleophile (e.g., cyclicamine) can act as the scavenging or non-nucleophilic base, and thereforetwo moles of the functionalized nucleophile (e.g., cyclic amine) shouldbe employed per mole of the reactive styryl compound in the situationwhere a separate base is not employed. As in other embodiments, anexcess of any of the reactants may be employed, although an excess ofcinnamyl halide is not recommended.

In another embodiment, the functionalized styryl reagent is prepared byreacting a reactive styryl reagent with a functionalized electrophile.In this embodiment, the reactive styryl reagent can be defined by theformula XIV

where each R¹, R², R³, R⁴, and R⁶ is defined as above, and Z is anucleophile. Examples of nucleophiles include hydroxyl groups, primaryor secondary amines, thiogroups, or the metal salts thereof.

Examples of functionalized electrophiles include aminoalkyl halides,silyl halides, and reactive vinyl ethers (e.g., dihydropyran). As withthe previous embodiments, this reaction is preferably accomplished byreacting a 1:1 molar ratio of the reactive styryl reagent with thefunctionalized electrophile, although an excess of either compound maybe used. As those skilled in the art will appreciate, this reaction maypreferably proceed in the presence of catalysts or scavengers.

Useful organolithium reagents can be defined by the formula R¹¹Li, whereR¹¹ is a hydrocarbyl group as defined above. The preferred hydrocarbylgroups are alkyl groups containing 1 to about 6 carbon atoms. Thepreferred organolithium compound is n-butyllithium, which is readilycommercially available.

In one embodiment, the initiator is prepared in the presence of a smallamount of monomer, (e g., from about 2 to about 30 moles of monomer/mmolof lithium) outside the presence of the majority of the monomer to bepolymerized; i.e., monomer other than that which is intended to form themain chain of the resultant polymer. Or, the monomer is added a veryshort time after the organolithium reagent is added to thefunctionalized styryl compound. In this embodiment, the resultantinitiator will include a chain-extended substituent. This initiator canbe represented by the formula XV

where each R¹, R², R³, each R⁴, R⁵, R⁵, and A are as defined as above,and Y represents a chain-extended segment that results from thepolymerization of the small amount of monomer present during theformation of the initiator. In preferred embodiments, the segment Y willinclude from about 3 to about 20 units deriving from the monomer.

Polymerizations that employ the initiator prepared according to thisinvention may be employed within batch processes, continuous processes,metered batch process, or semi-continuous processes. The preferredpolymerization methods employ the chain extended initiator inasmuch asthe stability and solubility of the initiator are increased when chainextended. Polymerization is conducted in an anhydrous polar or non-polarsolvent, such as tetrahydrofuran (THF), a hydrocarbon solvent, such asthe various cyclic and acyclic hexanes, heptanes, octanes, pentanes,their alkylated derivatives, and mixtures thereof. The polymerization ispreferably conducted in the absence of air.

The initiators prepared according to the present invention can beemployed to polymerize any monomer that can be anionically polymerized.Useful monomers include conjugated diene monomers such as, but notlimited to, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene,2-phenyl-1,3-butadiene, isoprene, 1,3-pentadiene,2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, and4,5-diethyl-1,3-octadiene. In one embodiment, the conjugated dienemonomer are copolymerized with vinyl-substituted aromatic monomers suchas, but not limited to, styrene, 4-methylstyrene, α-methylstyrene,3,5-diethylstyrene, 4-propylstyrene, 2,4,6-trimethylstyrene,4-dodecylstyrene, 2,3,4,5-tetraethylstyrene,3-methyl-5-normal-hexylstyrene, 4-phenylstyrene,2-ethyl-4-benzylstyrene, 3,5-diphenylstyrene, 1-vinylnaphthalene,3-ethyl-1-vinylnaphthalene, 6-isopropyl-1-vinylnaphthalene,6-cyclohexyl-1-vinylnapthalene, 7-dodecyl-2-vinylnaphthalene, and thelike, and mixtures thereof.

In order to promote randomization in copolymerization and to controlvinyl content, a polar coordinator may be added to the polymerizationingredients. Amounts range between 0 and 90 or more equivalents perequivalent of lithium. The amount depends on the amount of vinyldesired, the level of styrene employed and the temperature of thepolymerization, as well as the nature of the specific polar coordinator(modifier) employed. Suitable polymerization modifiers include, forexample, ethers or amines to provide the desired microstructure andrandomization of the comonomer units.

Other compounds useful as polar coordinators are organic and includetetrahydrofuran (THF), linear and cyclic oligomeric oxolanyl alkanessuch as 2,2-bis(2′-tetrahydrofuryl) propane, di-piperidyl ethane,dipiperidyl methane, hexamethylphosphoramide, N-N′-dimethylpiperazine,diazabicyclooctane, dimethyl ether, diethyl ether, tributylamine and thelike. The linear and cyclic oligomeric oxolanyl alkane modifiers aredescribed in U.S. Pat. No. 4,429,091, owned by the Assignee of record,the subject matter of which relating to such modifiers is incorporatedherein by reference. Compounds useful as polar coordinators includethose having an oxygen or nitrogen hetero-atom and a non-bonded pair ofelectrons. Other examples include dialkyl ethers of mono and oligoalkylene glycols; “crown” ethers; tertiary amines such astetramethylethylene diamine (TMEDA); linear THF oligomers; and the like.

The amount of initiator employed in conducting anionic polymerizationscan vary widely based upon the desired polymer characteristics. In oneembodiment, it is preferred to employ from about 0.1 to about 100, andmore preferably from about 0.33 to about 10 mmol of lithium per 100 g ofmonomer.

The anionic polymerizations can be quenched by employing severaltechniques that are well known in the art. In one technique, aterminator is added that may impart a functionality to the tail end ofthe polymer or that may serve as a coupling agent. Suitable terminatorsinclude, but are not limited to, metal halides, organic halides,alcohols, carboxylic acids, inorganic acids, sulfonic acid, water, andmixtures thereof. Some specific examples of preferred terminatorsinclude tin tetrachloride, tributyl tin chloride, silicon tetrachloride,trioctyl tin chloride, dioctyl tin dichloride, carbon dioxide, andepoxides.

The characteristics of the resultant polymer can vary greatly byemploying techniques that are well known in the art. The molecularweight of the polymer (“base polymer”) that is produced in thisinvention is optimally such that a proton-quenched sample will exhibit agum Mooney (ML₁₊₄@100° C.) of from about 1 to about 150. In a preferredembodiment, the uncoupled polymer will have a number average molecularweight of from about 5,000,000 to about 1,000,000, and preferably fromabout 50,000 to about 300,000 as measured by using gel permeationchromatography (GPC) calibrated with polystyrene standards and adjustedfor the Mark-Houwink constants for the polymer in questions. Themolecular weight distribution of the polymer is preferably less than 2,more preferably less than 1.5, and even more preferably less than 1.3.

The functionalized polymers prepared with the initiators of thisinvention are particularly useful for use in preparing tire components.The functional polymers of this invention are particularly useful inpreparing tire components. These tire components can be prepared byusing the functional polymers of this invention alone or together withother rubbery polymers. Preferably, the functional polymers are employedin tread formulations, and these tread formulations will include fromabout 10 to about 100% by weight of the functional polymer based on thetotal rubber within the formulation. More preferably, the treadformulation will include from about 35 to about 90% by weight, and morepreferably from about 50 to 80% by weight of the functional polymerbased on the total weight of the rubber within the formulation. Thepreparation of vulcanizable compositions and the construction and curingof the tire is not affected by the practice of this invention.

In preparing the vulcanizable compositions of matter, at least onefiller may be combined and mixed or compounded with a rubber component,which includes the functional polymer of this invention as well as otheroptional rubber polymers. Other rubbery elastomers that may be usedinclude natural and synthetic elastomers. The synthetic elastomerstypically derive from the polymerization of conjugated diene monomers.These conjugated diene monomers may be copolymerized with other monomerssuch as vinyl aromatic monomers. Other rubbery elastomers may derivefrom the polymerization of ethylene together with one or more α-olefinsand optionally one or more diene monomers.

Useful rubbery elastomers include natural rubber, syntheticpolyisoprene, polybutadiene, polyisobutylene-co-isoprene, neoprene,poly(ethylene-co-propylene), poly(styrene-co-butadiene),poly(styrene-co-isoprene), and poly(styrene-co-isoprene-co-butadiene),poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene),polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber,epichlorohydrin rubber, and mixtures thereof. These elastomers can havea myriad of macromolecular structures including linear, branched andstar shaped. Other ingredients that are typically employed in rubbercompounding may also be added.

The rubber compositions may include fillers such as inorganic andorganic fillers. The organic fillers include carbon black and starch.The inorganic fillers may include silica, aluminum hydroxide, magnesiumhydroxide, clays (hydrated aluminum silicates), and mixtures thereof.

A multitude of rubber curing agents may be employed. For example, sulfuror peroxide-based curing systems may be employed. Also, see Kirk-Othmer,ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY, 3^(rd) Edition, Wiley Interscience,New York 1982, Vol. 20, pp. 365-468, particularly VULCANIZATION AGENTSAND AUXILIARY MATERIALS pp. 390-402, or Vulcanization by A. Y. Coran,ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, 2^(nd) Edition, JohnWiley & Sons, Inc., 1989, which are incorporated herein by reference.Vulcanizing agents may be used alone or in combination.

Other ingredients that may be employed include accelerators, oils,waxes, scorch inhibiting agents, processing aids, zinc oxide, tackifyingresins, reinforcing resins, fatty acids such as stearic acid, peptizers,and one or more additional rubbers.

Preferably, the vulcanizable rubber composition Is prepared by formingan initial masterbatch that includes the rubber component and filler.This initial masterbatch is mixed at a starting temperature of fromabout 25° C. to about 125° C. with a discharge temperature of about 135°C. to about 180° C. To prevent premature vulcanization (also known asscorch), this initial masterbatch generally excludes any vulcanizingagents. Once the initial masterbatch is processed, the vulcanizingagents are introduced and blended into the initial masterbatch at lowtemperatures in a final mix stage, which does not initiate thevulcanization process. Optionally, additional mixing stages, sometimescalled remills, can be employed between the masterbatch mix stage andthe final mix stage. Rubber compounding techniques and the additivesemployed therein are generally known as disclosed in the in TheCompounding and Vulcanization of Rubber, by Stevens in RUBBER TECHNOLOGYSECOND EDITION (1973 Van Nostrand Reinhold Company). The mixingconditions and procedures applicable to silica-filled tire formulationsare also well known as described in U.S. Pat. Nos. 5,227,425; 5,719,207;5,717,022, as well as EP 0890606, all of which are incorporated hereinby reference.

Where the vulcanizable rubber compositions are employed in themanufacture of tires, these compositions can be processed into tirecomponents according to ordinary tire manufacturing techniques includingstandard rubber shaping, molding and curing techniques. Typically,vulcanization is effected by heating the vulcanizable composition in amold; e.g., it is heated to about 170° C. Cured or crosslinked rubbercompositions may be referred to as vulcanizates, which generally containthree-dimensional polymeric networks that are thermoset. The otheringredients, such as processing aides and fillers, are generally evenlydispersed throughout the vulcanized network. Tire components of thisinvention preferably include tire treads. The rubber compositions,however, can also be used to form other elastomeric tire components suchas subtreads, sidewalls, body ply skims, bead fillers and the like.Pneumatic tires can be made as discussed in U.S. Pat. Nos. 5,866,171;5,876,527; 5,931,211; and 5,971,046, which are incorporated herein byreference.

In order to demonstrate the practice of the present invention, thefollowing examples have been prepared and tested. The examples shouldnot, however, be viewed as limiting the scope of the invention. Theclaims will serve to define the invention.

EXAMPLES Example 1

Preparation of Cinnamyl-HMI

To a solution of hexamethyleneimine (HMI) (31 g, 0.3 mol) incyclohexane, cinnamyl chloride (22.9 g, 0.15 mol) was added dropwise atroom temperature with stirring. After 24 hours of agitation at 65° C.,the amine chloride salt was filtered off and the resulting solution(cyclic-amino functionalized styryl compound) concentrated to a darkyellow oil. The product was purified by vacuum distillation (˜1 mm Hg,80° C.) to yield 22 g (68% yield). The structure was confirmed by ¹H NMRanalysis.

Preparation of Initiator

The BuLi-cinnamyl HMI initiator (chain extended) was prepared just priorto polymerization. A small amount of hexanes (61.6 g) was charged to anitrogen purged reactor. Butyllithium (1.6 M, 8.5 mL) was added followedby cinnamyl-HMI (4.49 M, 2.73 mL) prepared above. Butadiene monomer(21.8% in hexanes, 23.4 g), which was used for chain extension, and apolar modifier (1.6 M, 1.02 mL) were charged last. This mixture wasallowed to react with agitation at 50° C. for 1 hour and then useddirectly in the polymerization.

Reactor Batch Polymerization

The initiator prepared above was employed to polymerizepoly(styrene-co-butadiene) in a batch polymerization. Specifically, a5-Gallon reactor was charged with hexanes (5.95 lbs.), styrene (34% inhexanes, 3.11 lbs.), butadiene (21.8% in hexanes, 15.72 lbs.), and theBuLi-cinnamyl HMI initiator prepared above (13.6 mmol C—Li) were chargedand the reactor was heated in batch mode to 50° C. and temperaturepeaked at 60° C., the mixture was stirred an additional 45 minutes andcoupled with equal parts of tributyl tin chloride and tin tetrachloride.The resulting polymer was coagulated in isopropyl alcohol, antioxidant,drum-dried, and analyzed. The resultant polymer was analyzed for aminecontent and showed greater than 80% bound cyclic amine.

Reactor Semi-Batch Polymerization

The initiator prepared above was also employed in a semi-batchpolymerization. A 5-gallon reactor was charged with hexanes (6.59 lbs.)and butyllithium-cinnamyl HMI initiator (13.6 mmol C—Li), which wasprepared in a similar fashion to that described above. A mixture ofstyrene (34% in hexanes, 4.77 lbs.) and butadiene (21.87%, 13.42 lbs.)was added over a two-hour period to the 5-gallon reactor. The resultingcement was coupled with equal parts of tributyl tin chloride and tintetrachloride as above and the final polymer analyzed. The resultantpolymer was analyzed for amine content and showed greater than 80% boundcyclic amine.

Example 2

Preparation of Cinnamyl-O—CH₂-pyrene

To a solution of 1-pyrene methanol (5 g, 21.5 mmol) in THF (150 mL) wasadded NaH (2 g, 50 mmol). After stirring for 30 min., cinnamyl chloride(4.3 g, 28.7 mmol) was added drop wise. After 2.5 h of reflux, thereaction was quenched with water and the two layers separated. Theorganic solution was washed with water (2×100 mL), brine (2×100 mL),dried over MgSO₄ and concentrated to an orange oil. The product waspurified by column chromatography (1:1, CH₂Cl₂:hexanes) to yield 5 g (67% yield). The structure was confirmed by ¹H NMR analysis.

In situ Formation of Initiator and Subsequent Polymerization

The BuLi-Cinnamyl pyrene initiator was prepared in situ. A purged glassreactor (AKA bottle) was prepared in the standard fashion. Hexanes (54.6g) and butadiene blend (22%, 45.6 g) were charged to the bottle followedby Buli (0.63 mL, 1.68 M) and cinnamyl-pyrene (0.8 mmol). The polarmodifier (0.13 mL, 1.6 M) was charged last. This mixture was allowed toreact with agitation at 50° C. for 1 h. After quenching with IPA anddrying, the presence of the functional group was confirmed by ¹H NMR.).

Example 3

Preparation of Cinnamyl-O-tetrahydropyran

A solution of cinnamyl alcohol (10.6, 19 mmol) and dihydropyran (7.3 g,87 mmol) in dichloromethane (200 mL) was prepared. A catalytic amount ofacid (p-toluene sulfonic acid) (20 mg) was added and the mixture stirredat room temperature under nitrogen for 4 hours. The reaction was dilutedwith a 5% sodium dicarbonate solution and the two layers separated. Theaqueous layer was extracted once with diethyl ether (100 mL). Theorganic solutions were combined and washed with water (100 mL), brine(100 mL), dried over MgSO₄ and concentrated to a yellow oil. The productwas pure as evidenced by ¹H NMR analysis (16 g: 93% yield).

In situ Formation of Initiator and Subsequent Polymerization

The BuLi-Cinnamyl-O-tetrahydropyran initiator was prepared in situ. Apurged glass reactor (AKA bottle) was prepared in the standard fashion.Hexanes (54.6 g) and butadiene blend (22%, 45.6 g) were charged to thebottle followed by BuLi (0.63 mL, 1.68 M) and cinnamyl-O-tetrahydropyran(0.8 mmol). The polar modifier (0.13 mL, 1.6 M) was charged last. Thismixture was allowed to react with agitation at 50° C. for 1 h. Afterquenching with IPA and drying, the presence of the functional group wasconfirmed by ¹H NMR.

Various modifications and alterations that do not depart from the scopeand spirit of this invention will become apparent to those skilled inthe art. This invention is not to be duly limited to the illustrativeembodiments set forth herein.

1. A process for preparing a functionalized anionic polymerizationinitiator, the process comprising: combining a functionalized styrylcompound and an organolithium compound, where the functionalized styrylcompound is defined by the formula X

where each R¹ is independently hydrogen or a hydrocarbyl group, R² ishydrogen or a hydrocarbyl group, R³ is hydrogen or a hydrocarbyl group,each R⁴ is independently hydrogen or a monovalent organic group, R⁶ is acovalent bond or a hydrocarbylene group, and A is a functional group. 2.An anionic polymerization initiator defined according to the formula I:

where each R¹ is independently hydrogen or a hydrocarbyl group, R² ishydrogen or a hydrocarbyl group, R³ is hydrogen or a hydrocarbyl group,each R⁴ is independently hydrogen or a monovalent organic group, R⁵ is ahydrogen atom or a hydrocarbyl group, where at least one of R³ or R⁵ ishydrocarbyl, R⁶ is a covalent bond or a hydrocarbylene group, and A is afunctional group selected from the group consisting of amine groups,phosphines groups, ether groups, thio ether groups, seleno groups, silylgroups, alkyl tin groups, and short-chain thermoplastic polymersegments.
 3. A polymer prepared by a process of comprising the steps of:polymerizing monomer with an initiator that is prepared by combining afunctionalized styryl compound and an organolithium compound, where thefunctionalized styryl compound is defined by the formula X

where each R¹ is independently hydrogen or a hydrocarbyl group, R² ishydrogen or a hydrocarbyl group, R³ is hydrogen or a hydrocarbyl group,each R⁴ is independently hydrogen or a monovalent organic group, R⁶ is acovalent bond or a hydrocarbylene group, and A is a functional group. 4.The process of claim 1, where the functionalized styryl compound isN-(cinnamyl): -pyrrolidine, -3-methylpyrrolidine,-3,4-dimethylpyrrolidiene, -3,3-dimethylpyrrolidine, -piperidine,-4-methylpiperidine, -3-methylpiperidine, -morpholine,-4-methylpiperazine, -4-ethyl-piperazine, -4-propylpiperazine,-hexamethyleneimine, -trimethylperhydroazepine, -azacyclotridecane,-azacyclohexadecane, -azacycloheptadecene, -trimethylazabicycloöctane,-perhydroisoquinoline, or -perhydroindole.
 5. The process of claim 1,where said step of combining combines about 0.8 mmol of thefunctionalized styryl compound with about 1.0 mmol of the organolithiumcompound.
 6. The process of claim 1, where step of combining occurs inthe presence of about 1 to about 20 mmol of monomer in order to chainextend the initiator.
 7. The process of claim 1, where the functionalgroup A is defined by the formula III

where each R⁹ is independently hydrogen or a monovalent organic groupand a is an integer from 4 to about
 18. 8. The process of claim 1, wherethe functionalized styryl compound is prepared by combining a reactivestyryl compound and a functionalized nucleophile.
 9. The process ofclaim 1, where the functionalized styryl compound is prepared bycombining a reactive styryl compound and a functionalized electrophile.10. The polymer of claim 3, where the functionalized styryl compound isN-(cinnamyl): -pyrrolidine, -3-methylpyrrolidine,-3,4-dimethylpyrrolidiene, -3,3-dimethylpyrrolidine, -piperidine,-4-methylpiperidine, -3-methylpiperidine, -morpholine,-4-methylpiperazine, -4-ethyl-piperazine, -4-propylpiperazine,-hexamethyleneimine, trimethylperhydroazepine, -azacyclotridecane,-azacyclohexadecane, -azacycloheptadecene, -trimethylazabicycloöctane,-perhydroisoquinoline, or -perhydroindole.
 11. The polymer of claim 3,where said step of combining combines about 0.8 mmol of thefunctionalized styryl compound with about 1.0 mmol of the organolithiumcompound.
 12. The polymer of claim 3, where step of combining occurs inthe presence of about 1 to about 20 mmol of monomer in order to chainextend the initiator.
 13. The polymer of claim 3, where the functionalgroup A is defined by the formula III

where each R⁹ is independently hydrogen or a monovalent organic groupand a is an integer from 4 to about
 18. 14. The polymer of claim 3,where the functionalized styryl compound is prepared by combining areactive styryl compound and a functionalized nucleophile.
 15. Thepolymer of claim 3, where the functionalized styryl compound is preparedby combining a reactive styryl compound and a functionalizedelectrophile.
 16. A process for preparing a functionalized anionicpolymerization initiator, the process comprising: combining afunctionalized styryl compound and an organolithium compound, where thefunctionalized styryl compound is N-(cinnamyl): -pyrrolidine,-3-methylpyrrolidine, -3,4-dimethylpyrrolidiene,-3,3-dimethylpyrrolidine, -piperidine, -4-methylpiperidine,-3-methylpiperidine, -morpholine, -4-methylpiperazine,-4-ethyl-piperazine, -4-propylpiperazine, -hexamethyleneimine,-trimethylperhydroazepine, -azacyclotridecane, -azacyclohexadecane,-azacycloheptadecene, -trimethylazabicycloöctane, -perhydroisoquinoline,or -perhydroindole.
 17. The anionic polymerization initiator of claim 2,where the functional group A is an ether group defined by the formula


18. The anionic polymerization initiator of claim 2, where functionalgroup A is a silyl group defined by the formula IX

where each R¹⁰ is independently selected from the group consisting of ahydrocarbyl group and an alkoxy group.
 19. The anionic polymerizationinitiator of claim 18, where the functional group A is selected from thegroup consisting of trimethyl silyl, triethyl silyl, dimethoxy methylsilyl, and dimethyl methoxy silyl.
 20. The anionic polymerizationinitiator of claim 2, where the functional group A is defined by theformula VII

where R⁷ is a hydrocarbyl group.
 21. The anionic polymerizationinitiator of claim 2, where the functional group A is defined by theformula VIII

where R⁷ is a hydrocarbyl group.
 22. The anionic polymerizationinitiator of claim 2, where the functional group A is defined by theformula V

where each R⁷ and R⁸ is independently a hydrocarbyl group.